harvester: [BUG][Multiple Cluster]Project Member cannot create resources in harvester-public ns

@noahgildersleeve Thanks for your testing. Sorry for the reproduced steps are not detailed. And there have a backend issue 2788 that makes harvester-public very confused.

Here are my reproduce steps:

1. Import Harvester into Rancher
2. Create cluster member user
3. Add a user to be a cluster member in Harvester via RBAC
4. Log out and log back in as a cluster member
5. Navigate to the Harvester dashboard via virtualization management
6. Create a project and a namespace
7. Navigate to the templates page
8. Try to create a new template in the harvester-public namespace

Expected Results Users can see the harvester-public namespace in the dropdown but cannot create it successfully.

And after issue 2788 was fixed, the harvester-public namespace will be hidden in the dropdown.

Explorer Test case:

1. Login Rancher as an admin user
2. Create a user whose name is “member”
3. Go to the local cluster -> Cluster member, Add a custom role: “View All Projects” for “member”
4. Create a new project with a new namespace, and then add “member” as the project read-only member.
5. Add a custom role: “Manage Workloads” for “member”
6. Login as the “member” user
7. Go to create workload page, check the dropdown menu

Expected Results No namespace options can be selected.